Mass distribution system for an archery bow

ABSTRACT

A mass based tuning system for an archery bow includes rotatable members or cams of the archery bow and a plurality of weights configured to removably attach to the rotatable members (e.g., cams). Modern compound bows have rotatable members (e.g. cams) that provide energy from bow limbs to the bowstring during release or firing of the bow. The shape of the rotatable members has the greatest effect on the energy delivery profile of the bow (i.e., energy or acceleration over time during release or firing of the bow), and mass distribution about the rotatable member has the second highest effect on the energy delivery profile of the bow. Weights are added to (or removed from) corresponding recesses in or holes through the rotatable member to alter the energy delivery profile of the bow in order to fine tune a bow to a given arrow.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application 62/787,342 entitled “MASS DISTRIBUTION SYSTEM FOR AN ARCHERY BOW” filed on Jan. 1, 2019.

A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO SEQUENCE LISTING OR COMPUTER PROGRAM LISTING APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

The present disclosure relates generally to the field of archery. More specifically, the present invention relates to a tuning system for a compound archery bow.

In modern archery, the term “spine” of an arrow refers to a measure of an arrow's stiffness (i.e., how much an arrow bends or flexes). Arrow spine is critical to how well a given bow and arrow combination will perform together because it directly affects arrow flight and accuracy. It is therefore of utmost importance to select an arrow having a spine that is matched to the way in which a bow delivers energy to the arrow. That is, select an arrow having a spine characteristic (i.e., amount of resistance to flex at different degrees of flex) complementary to the amount of energy (i.e., acceleration) delivered by the bowstring to the arrow over time during firing of the arrow. Unfortunately, the only way in which the match of a given bow and arrow combination can be optimized or “tuned” is by changing the draw weight (i.e., poundage) of the bow, which is undesirable. In the alternative, an archer can select an arrow with a different spine. However, matching an arrow spine to a given bow requires significant trial and error, and switching arrows is expensive and necessitates the repeating of along tuning setup procedure. Accordingly, what is needed are improvements in archery bows.

BRIEF SUMMARY OF THE INVENTION

Aspects of the present invention provide a mass based tuning system for an archery bow. Modern compound bows have rotatable members (e.g. cams) that provide energy from bow limbs to the bowstring during release or firing of the bow. The shape of the rotatable members has the greatest effect on the energy delivery profile of the bow (i.e., energy or acceleration over time during release or firing of the bow), and mass distribution about the rotatable member has the second highest effect on the energy delivery profile of the bow. Weights are added to (or removed from) corresponding recesses in or holes through the rotatable member to alter the energy delivery profile of the bow in order to fine tune a bow to a given arrow.

In one aspect, a mass distribution system for an archery bow includes a rotatable member. The rotatable member is configured to mount to a limb of the archery bow at a distal end of the archery bow and engage a strain of the archery bow such that an axis of rotation of the rotatable member extends laterally with respect to the archery bow when mounted on the archery bow. The rotatable member includes a recess configured to receive at least a portion of a weight therein such that the weight alters a rotational balance of the rotatable member when received in the recess.

In another aspect, the mass distribution system for an archery bow includes a plurality of weights. The plurality of weights is configured to removably attach to a rotatable member of the archery bow to redistribute mass throughout the body of the rotatable member. The plurality of weights thereby influence how the archery bow to which the rotatable member is mounted delivers energy to an arrow shot from the archery bow. That is, moving or changing a weight attached to the rotatable member alters an energy delivery profile of the bow to which the weight and rotatable member are attached.

In another aspect, an archery bow includes a mass distribution system. This includes a rotatable member. The rotatable member is configured to mount to a limb of the archery bow at a distal end of the archery bow and engage a strain of the archery bow such that an axis of rotation of the rotatable member extends laterally with respect to the archery bow when mounted on the archery bow. The rotatable member includes a recess configured to receive at least a portion of a weight therein such that the weight alters a rotational balance of the rotatable member when received in the recess.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a side perspective view of a compound archery bow according to one embodiment of the invention.

FIG. 2 is a partially exploded isometric view of a mass distribution system of the compound archery bow of FIG. 1.

FIG. 3 is an elevated perspective view of a weighted body shown in FIG. 2.

FIG. 4 is a bottom perspective view of the weighted body shown in FIG. 3.

FIG. 5 is a perspective detail view of a portion of the compound archery bow of FIG. 1 with the mass distribution system of FIGS. 2-4 installed therein.

Reference will now be made in detail to optional embodiments of the invention, examples of which are illustrated in accompanying drawings. Whenever possible, the same reference numbers are used in the drawing and in the description referring to the same or like parts.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.

To facilitate the understanding of the embodiments described herein, a number of terms are defined below. The terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity, but rather include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as set forth in the claims.

As described herein, an upright position is considered to be the position of apparatus components while in proper operation or in a natural resting position as described herein. As used herein, the upright position of a modern compound archery bow is when held by a user in a vertical orientation ready to draw and/or release (see FIG. 1). As used herein, archery bow refers to modern compound single limb or split limb bows or a compound crossbow. The upright position of a crossbow as described herein is when held by a user generally vertically (i.e., sideways) such that the limbs extend generally vertically. Forward or proximal is generally the direction in which a projectile is propelled from the archery bow when shot, and rearward or distal is generally toward a user shooting the archery bow. Vertical, horizontal, above, below, side, top, bottom and other orientation terms are described with respect to this upright position during operation unless otherwise specified. The term “when” is used to specify orientation for relative positions of components, not as a temporal limitation of the claims or apparatus described and claimed herein unless otherwise specified. The terms “above”, “below”, “over”, and “under” mean “having an elevation or vertical height greater or lesser than” and are not intended to imply that one object or component is directly over or under another object or component.

The phrase “in one embodiment,” as used herein does not necessarily refer to the same embodiment, although it may. Conditional language used herein, such as, among others, “can,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without operator input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.

Referring to FIG. 1, an archery bow 10 includes a riser 12 having an upper end 14 and a lower end 16. An upper limb 18 has a proximal end 22 coupled to the upper end 14 of the riser 12 and a distal end 26 rotatably coupled to a first rotatable member 30. A lower limb 20 has a proximal end 24 coupled to the lower end 16 of the riser 12 and a distal end 28 rotatably coupled to a second rotatable member 32. The proximal ends 22, 24 of the limbs 18, 20 are coupled to the upper and lower ends 14, 26, respectively, of the riser 12 by limbs caps 36, 38.

In some embodiments, each limb of the bow 10 is a split limb 18 comprising two limb pieces 18 a, 18 b oriented in parallel with one another. The limb pieces 18 a, 18 b define a space between them in which the rotatable member 30 is receivable. A drawstring 34 (i.e., string or bowstring) is connected between (e.g., wound around) the first and second rotatable members 30, 32 such that when the drawstring 34 is drawn back prior to shooting an arrow, the drawstring 34 causes the distal ends 26, 28 of first and second limbs 18, 20 to bend toward one another. First and second power cables 34 a and 34 b can be connected between the first and second rotatable members 30 and 32 rotatably mounted on distal ends 26 and 28 of upper and lower limbs 18 and 20, respectively. The power cables 34 a, 34 b assist a user with drawing back the drawstring 34 of the bow 10. When the drawstring 34 is released, the bent limbs 18, 20 spring back to a predrawn or undrawn position (and oscillate somewhat thereabout until such oscillations subside) such that the drawstring 34 returns to an undrawn position of the drawstring 34 and exerts a forward force on the arrow in the process which propels the arrow from the bow 10.

Referring to FIGS. 1-5, and archery bow 10 includes the string 34, a first limb 18, a second limb 20, and a riser 12. The first limb 18 is configured to support the first rotatable member 30, and the second limb 20 is configured to support the second rotatable member 32. The archery bow 10 includes a mass distribution system 40.

In one embodiment, the mass distribution system 40 includes a plurality of weights 50 configured to removably attach to rotatable member 30 of the archery bow 10 to redistribute mass throughout the body 42 of the rotatable member 30 and thereby modulate how the archery bow 10 to which the rotatable member 30 is mounted delivers energy to an arrow shot from the archery bow 10.

In one embodiment, the mass distribution system 40 includes a rotatable member 30 configured to mount to a limb 18 of the archery bow 10 at a distal end 26 of the archery bow 10 and engage the string 34 of the archery bow 10 such that an axis of rotation of the rotatable member 30 extends laterally with respect to the archery bow 10 when mounted on the archery bow 10. The rotatable member 30 includes a recess 45 configured to receive at least a portion of the weight 50 therein such that the weight 50 alters a rotational balance of the rotatable member 31 received in the recess 45. In one embodiment, the mass distribution system 40 further includes the weight 50. In one embodiment, a perimeter of the recess 45 in the body 42 of the rotatable member 30 is generally circular. The recess 45.

In one embodiment, the rotatable member 30 is configured to threateningly engage the weight 50. In one embodiment, the recess 45 of the rotatable member 30 has a threaded aperture 47 therein configured to threateningly engage the weight 50. In another embodiment, aperture 47 in the body 42 of the rotatable member 30 extends through the body 42 of the rotatable member 30, and the weight 50 includes 2 pieces configured to engage one another through the aperture 47 such that a portion of the weight 50 remains on either side of the body 42, securing the weight 52 the body 42. That is, the weight 50 includes 2 pieces configured to threateningly engage (e.g., bolt) to one another through the body 42 of the rotatable member 30.

In another embodiment, the recess 45 has threads configured to engage a rim 51 of the weight 50 such that the weight 50 screws directly into the recess 45 without the need for a protrusion 56 from a lower surface 54 of the weight 50 and a corresponding threaded aperture 47 in the body 42 of the rotatable member 30. In this embodiment, a socket 58 is used to rotate the weight 52 thread the weight 50 into or out of the recess 45.

In one embodiment, the mass distribution system 40 further includes the weight 50, and the weight 50 is a weighted disc. The weighted disc 50 has a thickness or depth corresponding to a depth of the recess 45 such that an upper surface 52 of the weight is generally coplanar with a lateral side of the body 42 of the rotatable member 30 when the weight 50 is received in the recess 45 of the body 42 of the rotatable member 30.

In one embodiment, the mass distribution system further includes a plurality of weighted discs 50. Weights of the plurality of weighted discs 50 have various different weights. Generally, the weights of the plurality of weighted discs 50 will be matched pairs. That is, each weight will have a corresponding weight of the same dimensions and weight that is substantially identical. The matched pairs may be marked as such by stampings, engravings, or color-coding. This enables a user or bow technician to ensure that the first rotatable member 30 and the second rotatable member 32 have the same (i.e., diametrically opposed) rotational balance as one another so that the bow 10 is balanced and unwanted vibrations during firing of the bow 10 are prevented.

In one embodiment, the recess 45 is a first recess, and the body 42 of the first rotatable member 30 has a second recess 304 configured to receive the weight 50. The second recess 304 is at least one of at a different distance from the axis of rotation of the rotatable member 30 or not diametrically opposing the first recess 45. That is, putting identical weights 50 in both the first and second recesses 45, 304 will not cause the weights 50 to cancel one another out such that the energy delivery profile of the bow 10 is not altered by installation of matched weights 50 in the first and second recesses 45, 304. Generally, the second recess 304 will be substantially identical to the first recess 45 with respect to an aperture 306 therein, diameter, and depth such that weights 50 may be interchanged between the second recess and first recess 304, 45.

In one embodiment, the mass distribution system 40 can include a pair of rotatable members 30, 32 having bodies 42, 44, a plurality of recesses 45, 304 defined in a surface of the bodies 42, 44, and a plurality of weighted discs 50 configured to be removably receivable in the recesses 45.

Each recess 45 can be circular in shape and have a depth that can be the same as or less than the thickness of the bodies 42, 44 of the rotatable members 30, 32. In some embodiments, the recesses 45, 304 can have a sidewall 49 provided with screw threads. In other embodiments, the sidewalls 49 of the recesses 45, 304 can be smooth and, optionally, tapered. In additional embodiments, the recesses 45 can include a threaded aperture 47, 306 located in the center of each recess 45, 304. The aperture 47, 306 can be defined through a portion of the thickness of each body 42, 44. In still other embodiments, the threaded aperture 47, 304 can be a through hole extending from one surface of the body 42, 44 to an opposing surface of the body.

Each weighted disc 50 can be generally circular in shape and sized so as to be receivable in each recess 45, 304. Each weighted disc 50 can include an upper surface 52, a lower surface 54, a rim 51, and a thickness extending from the upper surface 52 to the lower surface 54. The thickness of each weighted disc is preferably about the same as the depth of each recess 45 such that when the disc 50 is received in a recess 45, 304, the upper surface 52 of the disc 50 lies in substantially the same plane as the surface of the body 42, 44.

A socket 58 can be defined in the upper surface of each disc 50. In some embodiments, the socket 58 can be a slot in which a flat head screw driver or other similarly shaped tool is receivable to rotate the disc 50 about a central axis. In other embodiments, the socket 58 can be a socket for a hex key (i.e., hex head wrench). In still other embodiments, the socket 58 can be shaped to receive other tools commonly used to rotate fasteners such as screws and bolts (e.g., a Phillips head screwdriver, a torque bit, and the like).

In some embodiments, the rim 51 of each disc 50 can include screw threads complimentary to screw threads located on the sidewalls 49 of the recesses 45, 304. In additional embodiments, the lower surface 54 of one or more discs 50 can include a protrusion 56 extending outwardly from the lower surface 54 at an angle substantially normal to a plane of the lower surface 54. The protrusion 56 can be provided with screw threads 57 that are complimentary to the threads of the threaded aperture 47, 306 located in the center of each recess 45, 304.

Each weighted disc 50 can be made of virtually any suitably hard and dense polymeric or metallic material. In some embodiments, the discs 50 can be made of the same material as the bodies 40, 42 of rotatable members 30, 32. In other embodiments, the discs 50 can be made of one or more different materials than the bodies 40, 42 of rotatable members 30, 32. In some embodiments, the discs 50 are formed from a metallic material having a greater density than the density of bodies 40, 42. In certain embodiments, the discs can be formed from aluminum, steel, or a combination of both, such that different weighted discs 50 have different weights.

Any number of weighted discs 50 can be removably engaged with or disengaged from the bodies 42, 44 of rotatable members 30, 32 to redistribute mass around the bodies 42, 44 of rotatable members 30, 32 by screwing or unscrewing each disc 50 into or out of the one or more recesses, 45, 304. In this way, a user may tune or modulate how a bow 10 to which the rotatable members 30, 32 are attached delivers energy to an arrow without the need to adjust the draw weight (i.e., poundage) of the bow 10 or change to an arrow having a different spine. This advantageously allows the user to tune the accuracy of the bow with an arrow having a preselected spine, thereby eliminating the need for the user to test multiple arrows having different spines in order to optimize the accuracy of the bow.

It should be understood that it is not necessary to engage each weighted disc 50 with each recess 45, 304. Indeed, it can be desirable to engage none, one or more discs 50 with none, one or more recesses 45, 304 to achieve a desired tune for an arrow with a preselected spine. Multiple configurations of discs 50 and recesses 45, 304 are possible. For example, if a given arrow is too stiff, a user can add one or more weighted discs 50 to the body 42, 44 of one or both rotatable members 30, 42 to cause the arrow to fly straighter. Alternatively, if a given arrow is too flexible, a user can remove one or more weighted discs 50 from the body 42, 44 of one or both rotatable members 30, 42 to cause the arrow to fly straighter. In both cases, such tuning can be achieved without increasing or decreasing the poundage of the bow or changing to an arrow having a different spine.

This written description uses examples to disclose the invention and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

It will be understood that the particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention may be employed in various embodiments without departing from the scope of the invention. Those of ordinary skill in the art will recognize numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.

All of the compositions and/or methods disclosed and claimed herein may be made and/or executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of the embodiments included herein, it will be apparent to those of ordinary skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.

Thus, although there have been described particular embodiments of the present invention of a new and useful MASS DISTRIBUTION SYSTEM FOR AN ARCHERY BOW it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following 

What is claimed is:
 1. A mass distribution system for an archery bow, comprising: a rotatable member configured to mount to a limb of the archery bow at a distal end of the archery bow and engage a string of the archery bow such that an axis of rotation of the rotatable member extends laterally with respect to the archery bow when mounted on the archery bow; wherein the rotatable member comprises a recess configured to receive at least a portion of a weight therein such that the weight alters a rotational balance of the rotatable member when received in the recess.
 2. The mass distribution system of claim 1, wherein the mass distribution system further comprises the weight.
 3. The mass distribution system of claim 1, wherein a perimeter of the recess is generally circular.
 4. The mass distribution system of claim 1, wherein the rotatable member is configured to threadingly engage the weight.
 5. The mass distribution system of claim 1, wherein the recess of the rotatable member has a threaded aperture therein configured to threadingly engage the weight.
 6. The mass distribution system of claim 1, wherein: the mass distribution system further comprises the weight; the weight is a weighted disc; and the weight has a thickness corresponding to a depth of the recess such that an upper surface of the weight is generally coplanar with a lateral side of the rotatable member when the weight is received in the recess of the rotatable member.
 7. The mass distribution system of claim 1, wherein: the mass distribution system further comprises the weight; the weight is a weighted disc; the weighted disc is one of a plurality of weighted discs; the mass distribution system further comprises the plurality of weighted discs; weighted discs of the plurality of weighted discs have different weights; weighted discs of the plurality of weighted discs are removably receivable in the recess to redistribute mass throughout the body of the rotatable member and thereby modulate how the archery bow to which the rotatable member is mounted delivers energy to an arrow shot from the archery bow.
 8. The mass distribution system of claim 1, wherein: the rotatable member is a first rotatable member; the mass distribution system further comprises a second rotatable member; the weight is one weight of a plurality of weights of the mass distribution system; and at least two weights of the plurality of weights are substantially identical.
 9. The mass distribution system of claim 1, wherein: the recess is a first recess; the rotatable member is a non-circular cam and has a second recess configured to receive a weight; and the second recess is at least one of at a different distance from the axis of rotation or not diametrically opposing the first recess.
 10. A mass distribution system for an archery bow, comprising: a plurality of weights configured to removably attach to a rotatable member of the archery bow to redistribute mass throughout the body of the rotatable member and thereby modulate how the archery bow to which the rotatable member is mounted delivers energy to an arrow shot from the archery bow.
 11. An archery bow comprising: a mass distribution system comprising: a rotatable member configured to mount to a limb of the archery bow at a distal end of the archery bow and engage a string of the archery bow such that an axis of rotation of the rotatable member extends laterally with respect to the archery bow when mounted on the archery bow; wherein the rotatable member comprises a recess configured to receive at least a portion of a weight therein such that the weight alters a rotational balance of the rotatable member when received in the recess.
 12. The archery bow of claim 11, wherein the mass distribution system further comprises the weight.
 13. The archery bow of claim 11, wherein a perimeter of the recess is generally circular.
 14. The archery bow of claim 11, wherein the rotatable member is configured to threadingly engage the weight.
 15. The archery bow of claim 11, wherein the recess of the rotatable member has a threaded aperture therein configured to threadingly engage the weight.
 16. The archery bow of claim 11, wherein: the mass distribution system further comprises the weight; the weight is a weighted disc; and the weight has a thickness corresponding to a depth of the recess such that an upper surface of the weight is generally coplanar with a lateral side of the rotatable member when the weight is received in the recess of the rotatable member.
 17. The archery bow of claim 11, wherein: the mass distribution system further comprises the weight; the weight is a weighted disc; the weighted disc is one of a plurality of weighted discs; the mass distribution system further comprises the plurality of weighted discs; weighted discs of the plurality of weighted discs have different weights; weighted discs of the plurality of weighted discs are removably receivable in the recess to redistribute mass throughout the body of the rotatable member and thereby modulate how the archery bow to which the rotatable member is mounted delivers energy to an arrow shot from the archery bow.
 18. The archery bow of claim 11, wherein: the rotatable member is a first rotatable member; the mass distribution system further comprises a second rotatable member; the weight is one weight of a plurality of weights; and at least two weights of the plurality of weights are substantially identical.
 19. The archery bow of claim 11, wherein: the recess is a first recess; the rotatable member is a non-circular cam and has a second recess configured to receive a weight; and the second recess is at least one of at a different distance from the axis of rotation or not diametrically opposing the first recess.
 20. The archery bow of claim 11, wherein: the rotatable member is a first rotatable member; the mass distribution system further comprises a second rotatable member; the weight is one weight of a plurality of weights of the mass distribution system; and the archery boy further comprises: the string configured to engage and extend between the first rotatable member and the second rotatable member; a first limb configured to support the first rotatable member; a second limb configured to support the second rotatable member; and a riser configured to space the first limb from the second limb. 